Solved

PSU tests OK but when changing to another one, PC boots

Posted on 2013-11-30
11
505 Views
Last Modified: 2013-12-01
My PC stopped working the other day. Couldn't turn it on anymore. There was a green light that turned on, on the motherboard, other then that, nothing. No fans, no beeps, nothing on the display. Tested the PSU with a PSU tester, it tested OK. Every voltage and measurement within its range. Still when changing to a different PSU, everything boots and starts as normal. Any known possible explanations to this?
0
Comment
Question by:itnifl
  • 3
  • 2
  • 2
  • +3
11 Comments
 
LVL 15

Expert Comment

by:Insoftservice
ID: 39686861
Check whether your monitor is attached properly to your display card.
Did your whether processor is attached properly
0
 
LVL 2

Author Comment

by:itnifl
ID: 39686924
If any of those were not attached properly, I would get the same result with both PSU's. Both PSU's test fine, but computer does not boot with the old one. Re-tested several times.
0
 
LVL 93

Accepted Solution

by:
John Hurst earned 200 total points
ID: 39686950
Every voltage and measurement within its range

Any decent Voltmeter would not present a load to the power supply outputs. This is normal.

So then it is within reason that the old problem supply was unable to supply the required load but when you measured it, it said the voltage was OK.

I think this is what you are seeing.

... Thinkpads_User
0
Easy, flexible multimedia distribution & control

Coming soon!  Ideal for large-scale A/V applications, ATEN's VM3200 Modular Matrix Switch is an all-in-one solution that simplifies video wall integration. Easily customize display layouts to see what you want, how you want it in 4k.

 
LVL 32

Assisted Solution

by:willcomp
willcomp earned 175 total points
ID: 39686951
I've seen the same thing several times - PSU tests OK but will not boot system. Generally, that means output (watts) on the one of the rails has dropped and there is not enough wattage to boot the PC. Voltages are in range, but wattage is insufficient.
0
 
LVL 70

Expert Comment

by:garycase
ID: 39687168
As willcomp noted, this simply means the voltages are okay, but the current capacity of the old PSU has deteriorated to where it can no longer power your system.    I'd simply toss the old power supply.    Just be glad it was such a simple problem :-)
0
 
LVL 93

Expert Comment

by:John Hurst
ID: 39687172
These are pretty much the same answers as I gave earlier when I said (a) a voltmeter does not load a circuit and (b) the problem supply was not able to provide the required current.

... Thinkpads_User
0
 
LVL 32

Expert Comment

by:willcomp
ID: 39687561
@thinkpads_user - note times on our responses. I was typing when you posted your answer.
0
 
LVL 92

Expert Comment

by:nobus
ID: 39687817
when i test a PS, i always apply a load to the different voltage rails : 12 V, 5 V, and 3.3 V
i made a rig of car lamps for 12 V loads, and use resistor chains for the others.

another cause that it does not start, can be bulging or leaking capacitors inside the PS
aften you have to repalce only a couple to get it working again
here's how they look :
c
0
 
LVL 2

Author Closing Comment

by:itnifl
ID: 39687838
Thanks guys! This is great. i'll just toss the old one and use the new one. I don't want to spend time trying to repair it. I am not familiar with such work, would end up spending more time then interests me, and therefore just opt for the simplest solution :)
0
 
LVL 93

Expert Comment

by:John Hurst
ID: 39688039
@itnifl - Thanks for the update. In this case, replacement is probably the right answer.

.... Thinkpads_User
0
 
LVL 92

Expert Comment

by:nobus
ID: 39688175
nearly all bad PS's  i had in have been repaired
0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

In this article we have discussed the manual scenarios to recover data from Windows 10 through some backup and recovery tools which are offered by it.
A clone is a duplicate copy. Sheep have been cloned and maybe someday even people will be cloned, but disk cloning (performed by the hard drive cloning software) is a vital tool used to manage and protect data. Let’s look at what hard drive cloning …
The viewer will learn how to successfully create a multiboot device using the SARDU utility on Windows 7. Start the SARDU utility: Change the image directory to wherever you store your ISOs, this will prevent you from having 2 copies of an ISO wit…
The viewer will learn how to successfully download and install the SARDU utility on Windows 8, without downloading adware.

840 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question